
package org.apache.osgimaker.analyse.algorithm.dependency;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

import org.apache.osgimaker.analyse.algorithm.util.AndStringPattern;
import org.apache.osgimaker.analyse.algorithm.util.NotStringPattern;
import org.apache.osgimaker.analyse.algorithm.util.OrStringPattern;
import org.apache.osgimaker.analyse.algorithm.util.StringPattern;
import org.apache.osgimaker.analyse.algorithm.util.WildCardPattern;


/**
 * Parser for a dependency definition file.
 * 
 */
public class DependencyDefinitionParser
{
  public static final String INDEPENDENT_OF_KEY_WORD = "independentOf";
  public static final String EXCLUDING_KEY_WORD = "excluding";
  public static final String DIRECTLY_INDEPENDENT_OF_KEY_WORD = "directlyIndependentOf";
  public static final String DEPENDENT_ONLY_ON_KEY_WORD = "dependentOnlyOn";
  public static final String CHECK_KEY_WORD = "check";
  public static final String LAYER_KEY_WORD = "layer";
  public static final String SHOW_KEY_WORD = "show";
  public static final String SETS_KEY_WORD = "sets";
  public static final String CLASS_CYCLES_KEY_WORD = "absenceOfClassCycles";
  public static final String PACKAGE_CYCLES_KEY_WORD = "absenceOfPackageCycles";
  public static final String IN_KEY_WORD = "in";
  public static final String LAYERING_OF_KEY_WORD = "layeringOf";
  public static final String STRICT_LAYERING_OF_KEY_WORD = "strictLayeringOf";
  private static final String[] INDEPENDENT 
      = new String[] {INDEPENDENT_OF_KEY_WORD, 
                      DIRECTLY_INDEPENDENT_OF_KEY_WORD, DEPENDENT_ONLY_ON_KEY_WORD};
  private static final String[] EXCLUDING = new String[] {EXCLUDING_KEY_WORD};
  private static final String PROP_DEF_BEGIN = "{";
  private static final String PROP_BEGIN = "${";
  private static final String PROP_END = "}";
  
  private final DependencyProperties _properties;
  private final ResultRenderer _renderer;
  final SetDefinitionRepository _setDefinitions 
                    = new SetDefinitionRepository();
  final LayerDefinitionRepository _layerDefinitions 
                    = new LayerDefinitionRepository();
  private final ArrayList _statements = new ArrayList();
  
  public DependencyDefinitionParser(String dependencyDefinition,
                                    DependencyProperties properties, 
                                    ResultRenderer renderer) 
  {
    _properties = properties;
    _renderer = renderer;
    try
    {
      StringBuffer buffer = new StringBuffer();
      BufferedReader reader = new BufferedReader(new StringReader(
              dependencyDefinition));
      String line;
      int lineNumber = 0;
      int lineNumberOfCurrentLogicalLine = 1;
      while ((line = reader.readLine()) != null)
      {
        lineNumber++;
        line = line.trim();
        if (!line.startsWith("#"))
        {
          buffer.append(line);
          if (line.endsWith("\\"))
          {
            buffer.deleteCharAt(buffer.length() - 1).append(' ');
          } else
          {
            String logicalLine = replaceProperties(new String(buffer).trim(), 
                                              lineNumberOfCurrentLogicalLine);
            if (logicalLine.length() > 0)
            {
              parseLine(logicalLine, lineNumberOfCurrentLogicalLine);
            }
            buffer.setLength(0);
            lineNumberOfCurrentLogicalLine = lineNumber + 1;
          }
        }
      }
    } catch (IOException e)
    {
      throw new IllegalArgumentException(e.toString());
    }
  }
  
  private String replaceProperties(String line, int lineNumber)
  {
    StringBuffer buffer = new StringBuffer();
    for (int i = 0; i < line.length(); )
    {
      int index = line.indexOf(PROP_BEGIN, i);
      if (index >= 0)
      {
        buffer.append(line.substring(i, index));
        i = line.indexOf(PROP_END, index);
        if (i < 0)
        {
          throwException("Missing '" + PROP_END + "'.", lineNumber, -1);
        }
        String name = line.substring(index + PROP_BEGIN.length(), i);
        i += PROP_END.length();
        String property = _properties.getProperty(name);
        if (property == null)
        {
          String message = "Undefines property " + line.substring(index, i);
          throwException(message, lineNumber, -1);
        } else
        {
          buffer.append(property);
        }
      } else
      {
        buffer.append(line.substring(i));
        i = line.length();
      }
    }
    return new String(buffer);
  }
  
  public Statement[] getStatements() 
  {
    return (Statement[]) _statements.toArray(new Statement[0]);
  }
  
  private void parseLine(String line, int lineNumber) {
    if (line.startsWith(PROP_DEF_BEGIN))
    {
      parsePropertyDefinition(line, lineNumber);
      return;
    }
    StringTokenizer tokenizer = new StringTokenizer(line);
    String[] tokens = new String[tokenizer.countTokens()];
    for (int i = 0; i < tokens.length; i++)
    {
      tokens[i] = tokenizer.nextToken();
    }
    String firstToken = tokens[0];
    if (firstToken.startsWith("["))
    {
      parseSetDefinition(tokens, lineNumber);
    } else if (firstToken.equals(SHOW_KEY_WORD))
    {
      parseShowStatement(tokens, lineNumber);
    } else if (firstToken.equals(LAYER_KEY_WORD))
    {
      parseLayerDefinition(tokens, lineNumber);

    } else if (firstToken.equals(CHECK_KEY_WORD))
    {
      parseCheckStatement(tokens, lineNumber);

    } else
    {
      throwException("Expecting either a property definition, a set name, '" 
                     + SHOW_KEY_WORD + "', '" + LAYER_KEY_WORD + "', or '" 
                     + CHECK_KEY_WORD + "'.", 
                     lineNumber, 0);
    }
  }
  
  private void parsePropertyDefinition(String line, int lineNumber)
  {
    int index = line.indexOf(PROP_END);
    if (index < 0)
    {
      throwException("Missing '" + PROP_END + "' in property definition.", 
                     lineNumber, -1);
    }
    String name = line.substring(PROP_DEF_BEGIN.length(), index);
    String def = line.substring(index + PROP_END.length()).trim();
    if (def.startsWith("=") == false)
    {
      throwException("Missing '=' in propety definition.", lineNumber, -1);
    }
    _properties.setProperty(name, def.substring(1).trim());
  }
  
  private void parseSetDefinition(String[] tokens, int lineNumber)
  {
    String setName = tokens[0];
    if (setName.endsWith("]") == false)
    {
      throwException("Set name has to end with ']'.", lineNumber, 0);
    }
    if (_setDefinitions.contains(setName))
    {
      throwException("Set " + setName + " already defined.", lineNumber, 0);
    }
    checkForEqualCharacter(tokens, lineNumber, 1);
    StringPattern[][] lists = getLists(tokens, lineNumber, EXCLUDING, 2);
    if (lists[0].length == 0 && lists[1].length == 0) 
    {
      throwException("Missing terms in set definition.", lineNumber, 2);
    }
    AndStringPattern definition = new AndStringPattern();
    if (lists[0].length > 0)
    {
      definition.appendPattern(createOrSequence(lists[0]));
    }
    if (lists[1].length > 0)
    {
      definition.appendPattern(new NotStringPattern(createOrSequence(lists[1])));
    }
    _setDefinitions.put(setName, definition);
  }
  
  private void checkForEqualCharacter(String[] tokens, int lineNumber, 
                                      int index)
  {
    if (tokens.length < index + 1 || !tokens[index].equals("="))
    {
      throwException("'=' missing.", lineNumber, index);
    }
  }

  private StringPattern createOrSequence(StringPattern[] patterns) 
  {
    OrStringPattern result = new OrStringPattern();
    for (int i = 0; i < patterns.length; i++)
    {
      result.appendPattern(patterns[i]);
    }
    return result;
  }
  
  private StringPattern createPattern(String term, int lineNumber, 
                                      int tokenIndex)
  {
    StringPattern pattern = _setDefinitions.getPattern(term);
    if (pattern == null) 
    {
      if (term.startsWith("[") && term.endsWith("]")) 
      {
        throwException("Set " + term + " is undefined.", 
                       lineNumber, tokenIndex);
      }
      if (term.indexOf('.') < 0 && term.indexOf('*') < 0 
              && term.length() > 0 && Character.isLowerCase(term.charAt(0)))
      {
        throwException("Patterns without a '.' and a '*' should not start "
                         + "with a lower-case letter: " + term, 
                       lineNumber, tokenIndex);
      }
      pattern = new WildCardPattern(term);
    }
    return pattern;
  }

  private void parseLayerDefinition(String[] tokens, int lineNumber)
  {
    if (tokens.length < 2) 
    {
      throwException("Missing layer name.", lineNumber, 1);
    }
    String layerName = tokens[1];
    if (_layerDefinitions.contains(layerName)) 
    {
      throwException("Layer '" + layerName + "' already defined.", 
                     lineNumber, 1);
    }
    checkForEqualCharacter(tokens, lineNumber, 2);
    if (tokens.length < 4) 
    {
      throwException("Missing terms in definition of layer '" 
                     + layerName + "'.", lineNumber, 3);
    }
    ArrayList layer = new ArrayList();
    for (int i = 3; i < tokens.length; i++) 
    {
      layer.add(createPattern(tokens[i], lineNumber, i));
    }
    StringPattern[] sets = new StringPattern[layer.size()];
    _layerDefinitions.put(layerName, (StringPattern[]) layer.toArray(sets));
  }
  
  private void parseShowStatement(String[] tokens, int lineNumber)
  {
    if (tokens.length < 2) {
      throwException("Missing display preference(s).", lineNumber, 1);
    }
    Preference[] preferences = new Preference[tokens.length - 1];
    for (int i = 0; i < preferences.length; i++)
    {
      preferences[i] = _renderer.getPreferenceFactory().get(tokens[i + 1]);
      if (preferences[i] == null) 
      {
        throwException("Unknown display preference: " + tokens[i + 1], 
                       lineNumber, i + 1);
      }
    }
    _statements.add(new ShowStatement(_renderer, preferences));
  }
  
  private void parseCheckStatement(String[] tokens, int lineNumber)
  {
    if (tokens.length < 2) 
    {
      throwException("Missing checking statement.", lineNumber, 1);
    }
    if (tokens[1].equals(STRICT_LAYERING_OF_KEY_WORD) 
        || tokens[1].equals(LAYERING_OF_KEY_WORD))
    {
      createLayeringStatement(tokens, lineNumber);
    } else if (tokens[1].equals(SETS_KEY_WORD))
    {
      createCheckSetStatements(tokens, lineNumber);
    } else if (tokens[1].equals(CLASS_CYCLES_KEY_WORD)
            || tokens[1].equals(PACKAGE_CYCLES_KEY_WORD))
    {
      createCyclesStatement(tokens, lineNumber);
    } else 
    {
      createDependencyStatement(tokens, lineNumber);
    }
  }
  
  private void createCyclesStatement(String[]  tokens, int lineNumber)
  {
    boolean packageCycles = tokens[1].equals(PACKAGE_CYCLES_KEY_WORD);
    if (tokens.length != 6)
    {
      throwException("Invalid statement.", lineNumber, tokens.length);
    }
    if (tokens[2].equals(">") == false)
    {
      throwException("'>' expected.", lineNumber, 2);
    }
    int size = 0;
    try
    {
      size = Integer.parseInt(tokens[3]);
    } catch (NumberFormatException e)
    {
      throwException("Number expected.", lineNumber, 3);
    }
    if (size < 1)
    {
      throwException("Size has to be >= 1", lineNumber, 3);
    }
    if (tokens[4].equals(IN_KEY_WORD) == false)
    {
      throwException("'in' expected.", lineNumber, 4);
    }
    StringPattern pattern = createPattern(tokens[5], lineNumber, 4);
    _statements.add(new CheckCyclesStatement(pattern, size, packageCycles, 
                                             _setDefinitions));
  }
  
  private void createCheckSetStatements(String[] tokens, int lineNumber)
  {
    if (tokens.length < 3)
    {
      throwException("No sets to check.", lineNumber, 2);
    }
    for (int i = 2; i < tokens.length; i++)
    {
      StringPattern pattern = createPattern(tokens[i], lineNumber, i);
      _statements.add(new CheckSetStatement(pattern, _setDefinitions));
    }
  }
  
  private void createLayeringStatement(String[] tokens, int lineNumber)
  {
    StringPattern[][] layers = new StringPattern[tokens.length - 2][];
    for (int i = 0; i < layers.length; i++) 
    {
      String name = tokens[i + 2];
      layers[i] = _layerDefinitions.getLayer(name);
      if (layers[i] == null)
      {
        throwException("Undefined layer '" + name + "'.", lineNumber, i + 2);
      }
    }
    boolean strict = tokens[1].equals(STRICT_LAYERING_OF_KEY_WORD);
    _statements.add(new LayeringStatement(layers, strict, _setDefinitions, 
                                          _layerDefinitions, _renderer));
  }
  
  private void createDependencyStatement(String[] tokens, int lineNumber)
  {
    StringPattern[][] lists = getLists(tokens, lineNumber, INDEPENDENT, 1);
    if (lists[0].length == 0) 
    {
      throwException("Missing start sets.", lineNumber, 1);
    }
    if (lists[1].length == 0) 
    {
      throwException("Missing end sets. Probably one of the following "
                     + "key words are missing: " 
                     + Arrays.asList(INDEPENDENT), lineNumber, tokens.length);
    }
    boolean directPathsOnly = DIRECTLY_INDEPENDENT_OF_KEY_WORD.equals(
                                                tokens[lists[0].length + 1]);
    _statements.add(new DependencyStatement(lists[0], lists[1], tokens[lists[0].length + 1], _setDefinitions,
                                            _renderer));
  }
  
  private StringPattern[][] getLists(String[] tokens, int lineNumber, 
                                     String[] keyWords, int startIndex)
  {
    ArrayList startSets = new ArrayList();
    ArrayList endSets = new ArrayList();
    ArrayList currentList = startSets;
    for (int i = startIndex; i < tokens.length; i++) 
    {
      String token = tokens[i];
      if (isAKeyWord(token, keyWords)) 
      {
        if (currentList == endSets) 
        {
          throwException("Invalid appearance of key word '" + token + "'.", 
                         lineNumber, i);
        }
        currentList = endSets;
      } else
      {
        currentList.add(createPattern(token, lineNumber, i));
      }
    }
    StringPattern[][] result = new StringPattern[2][];
    result[0] = (StringPattern[]) startSets.toArray(new StringPattern[0]);
    result[1] = (StringPattern[]) endSets.toArray(new StringPattern[0]);
    return result;
  }

  private boolean isAKeyWord(String token, String[] keyWords)
  {
    boolean result = false;
    for (int i = 0; i < keyWords.length; i++)
    {
      if (keyWords[i].equals(token))
      {
        result = true;
        break;
      }
    }
    return result;
  }

  private void throwException(String message, int lineNumber, 
                              int tokenIndex) 
  {
    StringBuffer buffer = new StringBuffer("Error in line ");
    buffer.append(lineNumber);
    if (tokenIndex >= 0)
    {
      buffer.append(" token ").append(tokenIndex + 1);
    }
    buffer.append(": ").append(message);
    throw new IllegalArgumentException(new String(buffer));
  }
}
